Gabapentin and pregabalin are commonly prescribed for neuropathic pain and seizure disorders. In overdose, they often cause drowsiness, dizziness, and impaired coordination. Severe poisoning is less common after isolated exposure, but it can occur. Opioids, other sedatives, and impaired renal clearance substantially change the assessment.

For clinicians, the initial priorities are to assess breathing and consciousness, identify co-ingestants, and determine whether renal dysfunction may prolong toxicity. The reported dose remains useful, but it cannot establish severity or disposition by itself.

What Recent Studies Show

A 2026 study identified 1,207 gabapentinoid poisoning presentations to emergency departments in Victoria, Australia, from 2009–2010 through 2023–2024. Of these, 49.5% were classified as intentional and 36.2% were reported to involve gabapentinoids alone. These findings document a substantial clinical burden in one Australian state; they do not establish a worldwide incidence trend. [1]

U.S. National Poison Data System investigators identified 124,161 reported exposures from 2012–2022 in which gabapentin or pregabalin was coded as the primary substance. Most had no or minor effects, but 22.1% met the study's definition of a serious medical outcome, including 96 fatalities. Importantly, the “serious medical outcome” category combined moderate effects, major effects, and death; it does not mean that 22.1% of patients experienced life-threatening toxicity. [2]

Primary-substance coding reflects the poison center's assessment of the substance most responsible for the observed effects. It does not prove that gabapentin or pregabalin alone caused an outcome, particularly in mixed exposures. NPDS also depends on cases reported to poison centers and available follow-up, so these figures represent surveillance records rather than the risk for every person who takes an excessive dose. [2]

For a broader explanation of how poison-center surveillance should be interpreted, see Hidden Patterns in National Poison Data System: Early Signals You're Missing.

Key Takeaways

• Isolated gabapentin or pregabalin exposure often produces limited CNS toxicity, but severe or fatal poisoning is possible.

• Opioids and other CNS depressants increase concern for respiratory depression. Underlying respiratory impairment and older age also increase risk. [3]

• Renal impairment can cause drug accumulation and substantially prolong recovery.

• Treatment is primarily supportive. Naloxone treats a suspected opioid component, not gabapentinoid toxicity itself.

• Hemodialysis is reserved for selected clinical circumstances; dialyzability alone is not an indication.

• Disposition depends on clinical recovery, co-ingestants, renal function, formulation, and intent rather than a universal observation time.

• Medical recovery after intentional self-poisoning is separate from the psychiatric or psychosocial assessment required for safe disposition.

Pharmacology That Matters in Poisoning

Gabapentin and pregabalin bind to the α2δ auxiliary subunit of voltage-gated calcium channels. They are structurally related to gamma-aminobutyric acid (GABA), but neither is a direct GABA-A or GABA-B receptor agonist. [4] [5]

Their pharmacokinetics differ, particularly in absorption.

These values describe pharmacokinetics, not overdose safety thresholds. More predictable pregabalin absorption does not make clinical severity predictable from dose alone. [4] [5]

Isolated Overdose

Gabapentin

A prospective poison-center series described 20 single-substance gabapentin exposures, with reported doses ranging from 50 mg to 35 g. Findings included drowsiness, dizziness, ataxia, nausea or vomiting, tachycardia, and hypotension. No patient required medical admission, and clinical effects resolved within 10 hours in most cases. [6]

This was a small observational study. It supports the conclusion that isolated gabapentin exposure often produces limited toxicity; it does not establish a safe dose or a universal observation period.

Current prescribing information describes overdose-associated double vision, tremor, slurred speech, drowsiness, altered mental status, dizziness, and lethargy. It also reports fatal respiratory depression after gabapentin overdose both alone and in combination with other CNS depressants. A markedly obtunded or hypoventilating patient therefore requires appropriate assessment and support even when the reported exposure is gabapentin alone. [4]

Pregabalin

An observational series of 488 pregabalin poisoning presentations included 59 isolated exposures. In that subgroup, sedation was generally mild; one patient developed coma and recovered with supportive care, three had brief seizures, and none developed respiratory depression. These observations describe that particular cohort and should not be interpreted as excluding severe isolated poisoning. [7]

The paper contains different overall coma and intubation counts in its narrative and Table 1. For that reason, those conflicting totals should not be converted into precise complication rates. The more consistent clinical finding is that severe depression of consciousness was predominantly associated with sedating co-exposures. [7]

Current pregabalin prescribing information reports reduced consciousness, confusion, anxiety or depression, agitation, and restlessness after overdose. Seizures, heart block, and deaths following both isolated and mixed exposures have also been reported. These postmarketing data do not provide reliable incidence estimates or establish causality in every case. [5]

Rietjens and colleagues combined 21 prospectively followed isolated poisonings with 13 individual cases from the published literature. Higher weight-adjusted doses were associated with greater toxicity, but substantial interindividual variability remained. Dose should therefore be interpreted alongside symptoms, underlying illness, and co-exposures rather than used as a universal cutoff separating mild from severe poisoning. [8]

Co-Ingestants and Respiratory Depression

Co-ingestants are among the most important determinants of clinical severity.

In the 488-presentation pregabalin series, 88% involved at least one co-ingestant and approximately four-fifths involved another sedating agent. Opioids and benzodiazepines were common. Coma occurred predominantly in patients with sedative co-exposures, and the results narrative reports that all intubated patients had taken a sedating co-ingestant. [7]

The exact coma and intubation totals should be interpreted cautiously because of the internal inconsistencies already noted in the published report. The clinically important conclusion is more robust: substantial CNS depression should prompt an active search for other sedatives.

FDA warns that serious, life-threatening, and fatal respiratory depression can occur with gabapentin or pregabalin, particularly when they are used with opioids or other CNS depressants or in patients with underlying respiratory impairment. Older adults are also at increased risk. [3]

These FDA warnings apply to prescribing safety as well as overdose assessment; they are not an overdose severity score.

Clinicians should ask specifically about prescription or illicit opioids, benzodiazepines, alcohol, sedative-hypnotics, and other medications that can impair consciousness or ventilation. A medication list alone may not capture what was actually taken.

Renal Impairment and Drug Accumulation

Both gabapentin and pregabalin depend heavily on renal elimination. Reduced kidney function can markedly prolong exposure, including when toxicity develops from repeated therapeutic dosing rather than one large ingestion.

Gabapentin's usual elimination half-life is approximately 5–7 hours in patients with normal renal function. In current prescribing information, the mean half-life increased to approximately 52 hours when creatinine clearance was below 30 mL/min. [4]

Pregabalin is likewise eliminated predominantly unchanged in urine, and its clearance is nearly proportional to creatinine clearance. [5]

Clinicians should therefore distinguish an acute overdose from accumulation during treatment. Review the prescribed regimen, recent dose changes, actual medication use, baseline renal function, and the current clinical trajectory.

Prolonged somnolence, confusion, ataxia, myoclonus, or other abnormal movements may suggest drug accumulation, but kidney disease does not establish that a gabapentinoid explains every neurological symptom. Serum creatinine alone is also not an indication for extracorporeal drug removal.

Clinical Assessment and Investigations

Initial evaluation should focus on airway protection, respiratory rate and effort, oxygenation, ventilation, circulation, and the degree and trajectory of sedation.

Clarify the medication, strength, formulation, estimated dose, ingestion time, intent, and possible co-ingestants. Chronic gabapentinoid use, renal disease, respiratory impairment, and recent changes from baseline function are particularly relevant.

Testing should address the clinical problem rather than follow a rigid gabapentinoid-specific panel:

• Check glucose in unexplained altered mental status.

• Assess electrolytes and renal function when clinically indicated, particularly with substantial symptoms or possible accumulation.

• Obtain a blood gas when hypoventilation or respiratory failure is suspected.

• Obtain an ECG in severe or mixed poisoning, or when cardiovascular abnormalities warrant it.

• Investigate plausible co-ingestants and alternative diagnoses.

Drug-specific gabapentin or pregabalin concentrations are not routinely available in many emergency settings. No universally validated serum concentration determines intubation, admission, discharge, or dialysis.

A positive medication history should not end the differential diagnosis. Profound coma may reflect an opioid or other sedative, hypoglycemia, intracranial disease, infection, or metabolic encephalopathy. Persistent cardiovascular instability or other findings disproportionate to the reported exposure warrant broader investigation.

For the general approach to poisoned patients, see Comprehensive Guidelines for Managing Poisoning in Adults.

Treatment

Supportive Care

There is no specific antidote for gabapentin or pregabalin poisoning. Management centers on maintaining adequate ventilation and circulation while the drug is eliminated. [5]

Provide airway support, oxygen, and assisted ventilation as required. Give fluids when clinically indicated, treat seizures, and correct important metabolic abnormalities.

Persistent coma, respiratory failure, recurrent seizures, or significant hypotension requires higher-acuity monitoring and supportive care.

Seizures

Ongoing or recurrent drug-induced seizures should be treated with benzodiazepines as first-line therapy. When seizures persist despite adequate benzodiazepine treatment, barbiturates or propofol are established second-line options in an appropriately monitored setting with airway and ventilatory support. [9]

This is an application of general drug-induced seizure management rather than a gabapentinoid-specific anticonvulsant protocol.

Respiratory Depression and Chronic Therapy

Management of respiratory depression may include temporarily reducing or withholding gabapentinoids and other CNS depressants under clinician supervision. Current gabapentin labeling specifically describes supportive measures and reduction or withdrawal of contributing CNS depressants when respiratory depression occurs. [4]

For chronic users, subsequent restarting, dose reduction, or tapering should account for renal function, withdrawal risk, and the underlying indication for treatment. Abrupt discontinuation should be avoided when clinically inappropriate.

Poison-Center Consultation

Medical-toxicology or poison-center consultation is particularly appropriate for severe toxicity, uncertain mixed exposures, substantial renal impairment, recurrent seizures, or consideration of extracorporeal treatment.

For more on specialist poison-center assessment, see The Role of Poison Center Calls: Managing Poisoning Cases from Emergency Calls to Critical Decisions.

Naloxone

Naloxone does not directly reverse gabapentin or pregabalin.

It should, however, be administered when an opioid component is suspected in a patient with clinically important respiratory depression. Ventilatory support should not be delayed while clinicians attempt to determine the complete exposure history.

Improved breathing with persistent sedation after naloxone may indicate a remaining non-opioid depressant effect. Continue to assess ventilation, airway protection, and additional co-ingestants; partial improvement after naloxone is not evidence that a patient is ready for discharge.

Activated Charcoal

No validated gabapentinoid-specific activated-charcoal protocol has been established.

The 2026 Clinical Toxicology Recommendations Collaborative evaluated numerous poisons using individualized, substance-specific risk assessment, but gabapentin and pregabalin were not among the agents for which a specific recommendation was established. [10]

After a recent potentially significant oral exposure, activated charcoal may therefore be considered according to general toxicology principles, taking into account the ingested substance and formulation, time since ingestion, expected toxicity, current symptoms, aspiration risk, and airway protection.

Gastrointestinal decontamination should never delay airway stabilization, ventilation, or other urgent supportive care. Do not induce vomiting at home.

When to Consider Hemodialysis

Gabapentin and pregabalin are dialyzable, but evidence that extracorporeal treatment improves clinical outcomes is limited.

Pregabalin prescribing information reports that approximately 50% of the plasma concentration can be removed during a four-hour hemodialysis treatment. [5]

That pharmacokinetic fact should not be interpreted as an indication to dialyze every patient.

The EXTRIP Workgroup's recommendations distinguish kidney function and clinical severity. [11]

The first two recommendations are weak recommendations, whereas the modality and cessation recommendations are strong. All are based on very low-quality clinical evidence. [11]

Kidney impairment alone does not make extracorporeal treatment necessary, and no universal gabapentin or pregabalin concentration serves as a dialysis trigger.

For broader principles of enhanced elimination, see Hemodialysis in Poisoning: A Comprehensive Guide for Healthcare Providers.

If extracorporeal treatment is performed, EXTRIP recommends monitoring patients in an appropriate setting for possible withdrawal symptoms. [11]

Observation and Disposition

There is no validated observation period that applies to every gabapentin or pregabalin exposure.

Decisions depend on formulation, timing, symptoms, renal function, co-ingestants, and intent. Improvement is necessary, but it must be interpreted alongside any remaining risk from the overall exposure.

A patient with mild, improving sedation after a confirmed isolated immediate-release ingestion and normal renal function has different monitoring needs from a patient with an uncertain formulation, multiple sedative co-ingestants, or significant renal impairment.

A patient evaluated soon after ingestion may also not yet have shown the full clinical effect. Document the exposure timeline and the trend across serial examinations.

Continue observation or admit when consciousness or ventilation remains impaired, symptoms recur, circulation is unstable, significant renal impairment is accompanied by ongoing toxicity, or a co-ingestant requires additional monitoring. Persistent confusion, unsafe gait, falls risk, or inability to perform usual self-care also weigh against discharge.

Severe toxicity requires admission at an appropriate level of monitored care.

Practical Discharge Checklist

Before medical discharge, confirm that:

• consciousness has returned to baseline without recurrent or worsening sedation;

• spontaneous ventilation and oxygenation are adequate without ongoing respiratory support;

• circulation is stable and significant abnormalities have resolved or have an appropriate management plan;

• the patient can mobilize safely at their usual functional level, when applicable;

• the expected course of the formulation and any co-ingestants has been considered;

• there is no unresolved need for continued monitoring or treatment;

• renal function, medication dosing, and risk of further accumulation have been addressed;

• the patient or caregiver understands return precautions and the follow-up plan.

This checklist is a practical clinical synthesis, not a validated discharge rule. Persistent confusion, unsafe gait, or recurrent sedation should not be dismissed simply because a reported dose seems small or a certain number of hours has elapsed.

Medical recovery and assessment after intentional self-poisoning are separate requirements. A patient who has recovered physiologically still needs an appropriate evaluation of self-harm risk and a safe psychiatric or psychosocial disposition plan.

Prevention and Medication Review

Gabapentinoid dosing should be reviewed when renal function changes, particularly after acute illness or new kidney impairment. Restarting the same regimen after toxicity without addressing impaired clearance may recreate the problem.

Patients should also be asked about prescribed and nonprescribed sedatives, alcohol, self-directed dose escalation, and use for psychoactive effects. When gabapentinoids are used with opioids or other CNS depressants, FDA recommends monitoring for sedation and respiratory depression. [3]

Discuss secure medication storage and discourage medication sharing. After an intentional exposure, medication access should form part of the safety plan.

For chronic users, subsequent dose reduction or discontinuation should account for withdrawal and the underlying condition being treated. Patients should not abruptly stop prescribed therapy without appropriate clinical guidance. [4] [5]

FAQ

Does a Reported Large Dose Automatically Require Dialysis?

No. The decision depends on clinical severity and renal clearance, not dose alone. EXTRIP suggests against extracorporeal treatment in severe poisoning with normal kidney function and supports considering it in selected severe cases with impaired kidney function. [11]

Can Toxicity Occur Without a Single Large Overdose?

Yes. Repeated dosing can produce accumulation when renal clearance is reduced. Review the patient's regimen and recent renal function rather than relying only on the amount taken at the most recent dose. [4] [5]

Is Improvement After Naloxone Enough to End Observation?

No. Naloxone treats an opioid component. Persistent sedation, recurrent respiratory depression, impaired mobility, or another co-ingestant may still require monitoring and treatment.

Emergency Help in the United States

For a suspected overdose in the United States, Poison Help at 1-800-222-1222 connects callers with a poison center 24 hours a day. [12]

Call 911 immediately if the person cannot be awakened, has significant difficulty breathing, has a seizure, collapses, or develops another life-threatening symptom.

Do not wait for severe symptoms before seeking poison-center advice after a potentially significant exposure.

Outside the United States, contact the local poison-information service or emergency medical system.